Renegade Thermostat Gone Wild: Temperature Chaos Alert

Had the exact same symptoms on my 2017 Jeep Compass last winter. The engine temperature fluctuated out of nowhere and the thermostat housing was the culprit. Initially thought it was just the temperature sensor, but diagnostic tests revealed a sticking thermostat that wasnt regulating coolant flow properly. The thermostat would either stay closed too long, causing engine overheating, or remain partially open, preventing proper warm-up. This is a common issue in these engines around the 150000km mark. The cooling system itself was fine, but the thermostat assembly needed complete replacement. Its a fairly technical job requiring specific knowledge of the cooling system layout. The thermostat housing needs precise installation to prevent leaks and ensure proper function. A misaligned housing can cause persistent issues. This is not a repair to experiment with, the consequences of a malfunctioning thermostat can lead to severe engine damage if left unaddressed. Would recommend finding a shop that specializes in Jeep repairs, especially if youre not confident in your current mechanic. The repair took about 3 hours of labor, including cooling system pressure testing afterward to ensure everything was properly sealed.

Thanks for confirming my suspicions about the thermostat. My Renegade showed those same exact symptoms, the unusual temperature swings were really concerning. Got it fixed last month and the car runs perfectly now, maintaining steady temperature like it should. Was curious about your repair costs? After replacing the thermostat, I kept an eye on the coolant system for a while to make sure there were no coolant leaks or other issues. Have you noticed any other problems since your repair?

Since getting the thermostat cooling circuit motor fixed at the shop, my Compass has been running flawlessly. The repair cost came to 350 Euro for the defective map thermostat replacement, which is pretty standard for this type of work. The temperature sensor now shows consistent readings, and the engine warms up normally. No coolant leaks or any other cooling system issues have surfaced in the months following the repair. The engine maintains steady operating temperature, and the cooling fan cycles normally. Its really important to catch these thermostat problems early before they can cause more serious engine damage. Good call on monitoring your coolant system after the repair, thats exactly what I did too. Its reassuring when you can see the temperature gauge staying right where it should be, instead of those worrying fluctuations we both experienced before.

Thanks everyone for the helpful feedback. Finally got around to having it fixed at a different shop than my usual one. Brought it in last week and the whole job cost 390 Euro, a bit more than expected but worth every cent. The new thermostat fixed all the temperature issues completely. The mechanic showed me the old thermostat and it was clearly stuck. He pressure tested the entire cooling system after the repair to make sure there were no coolant leaks. The temperature gauge now stays steady and the engine warms up properly in about 5-7 minutes. Really glad I didnt wait any longer since the mechanic mentioned this could have led to bigger engine problems. The cooling fan now cycles normally and the temperature sensor readings make sense. Much better experience with this new shop, they took time to explain everything and even showed me the faulty parts.